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TEST BANK FOR ESSENTIAL STATISTICS 3RD EDITION
ROBERT LATEST QUESTIONS AND 100% ACCURATE
ANSWERS.
"Null hypothesis - CORRECT ANSWER=> the hypothesis that there is no significant difference between
populations, or that the difference is in a direction opposite from that anticipated by the researcher."
"Research hypothesis - CORRECT ANSWER=> alternate hypothesis, is a statement that postulates that
there is a difference between poplulations or sometimes a difference in certain direction, positive or negative."
"Type I error - CORRECT ANSWER=> Rejecting null hypothesis when it is true"
"Type II error - CORRECT ANSWER=> Failing to reject a false null hypothesis"
“Data - CORRECT ANSWER=> Consists of information coming from observations, counts,
measurements, or responses."
"Data sets - CORRECT ANSWER=> Two types used to study in statistics:
-population -samples" "Data Set Examples: In a survey, 614 small business owners in the US were asked whether they thought their companys FB presence was valuable. 258 of the 614 said yes.
What is the population and sample & describe the sample data set? - CORRECT ANSWER=> The
population consists of the responses of all small business owners in the US. The sample consists of the 614 responses of the small business owners in the survey. **The sample is a subset of responses of business owners in the US...the sample data set consists of 258 "yes" owners & 356 owners who said "no"" "Data Set Examples: A survey of 1015 U.S. adults found that 32% have had to put off medical care for themselves or their
family in the past year due to cost. What are the data sets? - CORRECT ANSWER=> Population: results
from all adults in U.S. Sample: results from the 1015 U.S. adults included in the survey"
"Sample - CORRECT ANSWER=> A set of observations drawn from the population of interest. It should
be a representative of a population. Random sampling is best. Used in Inferential."
"Sample Example:
A survey of 500 spectators from a stadium with 42,000 spectators...what is the sample? - CORRECT
ANSWER=> The survey of 500 spectators is a sample bc it is a subset, or part, of the population of
42,000 spectators at the stadium" "Parameter Example: In January 2013, 60% of the governors of the 50 states in the USA were republicans. What is the
Parameter? - CORRECT ANSWER=> The 60% is the PARAMETER. It is the numerical description of the
total number of governors" "Statistic Example: The average annual salary for 35 of a company's 1200 accountants is $68,000. What is the Statistic? -
CORRECT ANSWER=> The $68,000 is a STATISTIC. It is a numerical description of a sample of annual
salaries" "Descriptive Stats Example: A survey of 202 pilots found that 20% admit that they have made a serious error due to sleepiness. What
is the descriptive statistic? - CORRECT ANSWER=> The statement "20% admit that they have made
serious errors due to sleepiness" is a descriptive statistic." "Inferential Statistics Example: An inference is drawn from the sample is that "an association exists between sleepiness and pilot error."
- CORRECT ANSWER=> Making this inference is an example of inferential stats"
"Qualitative - CORRECT ANSWER=> Attributes, lables, or nonnumerical entries
EX: eye colors of models since eye color is a nonnumerical attribute"
"Quantitative (N) - CORRECT ANSWER=> Numerical measurements or counts
EX: heights of hot air balloons"
"How is a sample related to a population? - CORRECT ANSWER=> a sample is a subset of a population"
"T or F:
A statistic is a measure that describes a population characteristic? - CORRECT ANSWER=> False, a
statistics is a measure that describes a sample characteristic" "T or F: A population is the collection of some outcomes, responses, measurements, or counts that are of
interest. - CORRECT ANSWER=> False. A population is the collection of all outcomes, responses,
measurements, or counts that are of interest."
"Suppose a survey of 510 women in the United States found that more than 58% are the primary investor in their household. Which part of the survey represents the descriptive branch of statistics?
Make an inference based on the results of the survey - CORRECT ANSWER=> descriptive statistic: 58%
of women in the sample are the primary investor in their household. inferential statistic: 58% of women the sample are the primay investor's in their houshold.." "In a recent study, volunteers who had 8 hours of sleep were three times more likely to answer questions correctly on a math test than were sleep-deprived participants. -identify the sample -the population -what part is descriptive stats?
-make an inference - CORRECT ANSWER=> the sample in the study is the responses of the volunteers in
the study. The population is the collection of the responses of all individuals who completed the math test descriptive stats: The statement "three times more likely to answer questions correctly" is an example of descriptive statistics. inferential stat: individuals who are not sleep deprived will be more likely to answer math questions correctly than individuals who are sleep deprived." "Suppose that a study based on a sample from a targeted population shows that people who own three or more televisions have more money than people who do not. -inferential stat
-what does the inferential stat incorrectly imply - CORRECT ANSWER=> inferential stat: people who
own three or more televisions have more money than people who own less than three televisions This inference may incorrectly imply that if you owned three or more televisions, then you would have more money than if you owned less televisions." "Using random digit dialing, researchers call 800 people and ask what obstacles keep them from exercising.
what sampling is used and what bias is present? - CORRECT ANSWER=> Simple random sampling is
used, since each number has an equal chance of being dialed, so all samples of 800 phone numbers have an equal chance of being selected. Bias: -Individuals may refuse to participate in the sample. This may make the sample less representative of the population. -Individuals may not be available when the researchers are calling. Those individuals that are available may not be representative of the population
-Telephone sampling only includes people who have telephones. People who own telephones may be older or wealthier on average, and may not be representative of the entire population." "Questioning students as they leave a university dorm, a researcher asks 351 students about their reading habits.
what sampling is this and what potential source of bias is present? - CORRECT ANSWER=> Convenience
sampling is used, because students are chosen due to convenience of location Bias: -Because of the personal nature of the question, students may not answer honestly. -The sample only consists of members of the population that are easy to get. These members may not be representative of the population." "Chosen at random, 420 customers at a grocery store are contacted and asked their opinions of the service they received.
what kind of sampling is this and what potential bias is present? - CORRECT ANSWER=> Simple random
sampling is used, since the business is selecting from its customers at random, and all samples of 420 customers have an equal chance of being selected. Bias: The wording of the question asked to the customers may influence them towards a particular response. The results would not be usable in this case." "Use the row of numbers shown below to generate 12 random numbers between 01 and 99.
90087 42075 28407 08801 82618 05237 05444 65936 - CORRECT ANSWER=>
"Why is eating eggs good for you? -Is the survey question biased?
-what is the best substitute question?? - CORRECT ANSWER=> -yes, it is biased
-how do you think eating eggs effects your health?" "How much do you sleep per night during an average week? -is the question biased
-what is a substitute - CORRECT ANSWER=> -No, its not biased because it does not lead the respondent
to any particular answer. -no substitute needed"
"Important info. to look for when organizing and describing data sets are its..... - CORRECT ANSWER=>
center, variability (spread), and shape"
"Population standard deviation formula - CORRECT ANSWER=> "
"Sample variance - CORRECT ANSWER=> "
"Sample standard deviation - CORRECT ANSWER=> "
"empirical rule - CORRECT ANSWER=> For data with a symmetric bell shaped distribution, the standard
deviation has the following characteristics: -About 68% of data lie within one standard deviation of the mean -about 95% of data lie within two standard deviations of the mean -about 99.7% of data lie within three standard deviations of the mean"
"Chebychev's theorem - CORRECT ANSWER=> the portion of any data set lying within K standard
deviations of the mean is at least.... 1 1- ____ K^ K=2: in any data set, at least 75% of data lie within 2 standard deviations of the mean K=3: in any data set, at least 88.9% of the data lie within 3 standard deviations of the mean"
"sample standard deviation for a frequency - CORRECT ANSWER=> n=the sum of frequencies
sigma frequency"
"a student scored in the 78% percentile on a exam. what does this mean? - CORRECT ANSWER=> Since
the student is in the 78th percentile, that means that 78% of the students who took the actuarial exam fall below that score. Therefore, the student scored higher than 78% of the total number of students"
"quartiles and percentiles - CORRECT ANSWER=> Quartiles
are special cases of percentiles. Upper Q is the 25th percentile, Upper Q is the 50th percentile, and Upper Q is the 75th percentile."
"second quartile - CORRECT ANSWER=> The second quartile is the median of an ordered data set. it is
equivalent to the 50th percentile"
"Inferential Statistics - CORRECT ANSWER=> Uses sample data to make a general estimate about the
larger population."
"Descriptive Statistics - CORRECT ANSWER=> Organize, summarize, and communicates a group of
numerical observations.. They are usually one statistic that describes a large amount of data."
"Variable - CORRECT ANSWER=> Observations of physical, attitudinal, and behavioral characteristics
that can take on different values."
"Discrete observation - CORRECT ANSWER=> Can take on only specific values (e.g. whole numbers); no
other values can exist between these numbers."
"Continuous observation - CORRECT ANSWER=> Can take on a full range of values (e.g., numbers out
to several decimal places); an infinite number of potential values exists."
"Nominal variable - CORRECT ANSWER=> Discrete: categorical or names."
"Ordinal Variables - CORRECT ANSWER=> Discrete: They have ranking or order."
"Interval variable - CORRECT ANSWER=> Continuous: A variable used for observations that have
numbers as their values; the distance (or interval) between pairs of consecutive numbers is assumed to be equal. (time & distance are continuous, but also identified as a ratio because zero has meaning for time & distance like when you run out of time, sometimes discrete such as # of times you have to get up early each week). They are whole numbers."
"Ratio variable - CORRECT ANSWER=> : Continuous: Same as intervals but have meaningful zero points.
Seldom discrete, # of times a rat pushes a button for food"
"Scale variable - CORRECT ANSWER=> A variable that meets the criteria for an interval variable or a
ratio variable. Is used for either ratio or interval."
"Level - CORRECT ANSWER=> A discrete value or condition that a variable can take on. Ex:gender is
variable, man or women are the levels."
"Independent variable - CORRECT ANSWER=> It has at least two levels that we either manipulate or
observe to determine its effects on the dependent variable."
"Confounding variable - CORRECT ANSWER=> Any variable that systematically varies with the
independent variable so that we cannot logically determine which variable is at work. Random assignment can control for confounding variables."
- Create a list of the full range of values from highest to lowest, including all values. These are the raw scores.
- Write in the frequency that appear."
"Expansion of a frequency table - CORRECT ANSWER=> Create another column named "Percentage" to
include the individual frequency divided by the total frequency to get thge percentage."
"creating a grouped frequency table - CORRECT ANSWER=> 1. Find the smallest and largest numbers in
the distribution table.
- Determine the full range of data, rounding as necessary. Subtract the lesser number from the greater number, then add 1.
- Determine the number of interval and the best interval size (recommended using 5 or 10 intervals). Name the first column "interval"
- Determine starting number and ending number entering individual ranges in table.
- Enter the count of each figure for each row, in the column named ""frequency""
"Grouped frequency tables - CORRECT ANSWER=> a visual depiction of data that reports frequencies
within a given interval rather than the frequencies for a specific value. Use this table when there are too many decimal places or there is too much data."
"Histogram - CORRECT ANSWER=> Similar to a bar graph but typically depict scale data with the values
of the variable on the x-axis and the frequencies on the y-axis."
"Upper class limit - CORRECT ANSWER=> The greatest number that can belong to a class"
"Lower class limit - CORRECT ANSWER=> The least number that can belong to a class"
"Midpoints - CORRECT ANSWER=> Take the low & high limits, add. Then divide by two."
"Grouped Frequency Histogram - CORRECT ANSWER=> 1. Calculate your midpoints for each range of
data
- Put these midpoints on the x-axis (starting graph at 0.
- Label the y-axis "frequency"
- Place bars on both sides, up to its frequency."
"Frequency polygons - CORRECT ANSWER=> A line graph with the x-axis representing values (or
midpoints of intervals) and the y-axis representing frequenciesj a dot is placed at the frequency or each value (or midpoint) and the dots are conected.
- Using the idea of the histogram, determine midpoints.
- Label the x-saxis with the variable of interest and either the values or the midpoints.
- Label y-axis "frequency"
- rather than bars above them, place a dot at the frequency where the midpoint is.
- Starting at first midpoint dot, draw a line connecting the dots."
"Shapes of distribution - CORRECT ANSWER=> a. Normal, symmetric distribution
b. Uniform distribution, even c. Skewed left distribution d. Skewed right distribution
- Unimodal - one
- Bimodal - two
- Multimodal - more than two"
"Uniform/rectangular - CORRECT ANSWER=> When all entries, or classes, in the distribution have
equal or approximately equal frequencies. A uniform distribution is also symmetric."
"Normal distributions - CORRECT ANSWER=> Data representation with a distinctive bell-shaped curve,
symmetric about the mean"
"Skewed Distribution - CORRECT ANSWER=> A distribution in which one of the tails of the distribution
is pulled away from the center" "Skewed right
(positively skewed) - CORRECT ANSWER=> The graph has a tail that elongates to the right.
*the mode is less than the median which is less than the mean"
"Floor effect - CORRECT ANSWER=> Positively skewed to the right, constraint prevent a variable from
takim on values below a point.."
"Skewed left (negatively skewed) - CORRECT ANSWER=> A frequency distribution is skewed when the
"tail" of the graph elongates more to one side than to the other. The mean is lower than the median."
"Ceiling effect - CORRECT ANSWER=> Negatively skewed to left where a constraint prevents a variable
from taking on values above a given number."
"Misleading Graphs - CORRECT ANSWER=> Graphs that are constructed incorrectly to cause confusion
and can lead to false assumptions."
"False face validity lie - CORRECT ANSWER=> The method seems to represent what it says but when
you dig a little deeper it does not."
"Biased scale lie - CORRECT ANSWER=> Pushes people toward certain responses or biased
interpretations. (ex: used biased scales, poor, fair, good, great)."
"Sneaky sample lie - CORRECT ANSWER=> When participants are preselected or self-selected to
provide data in a certain way. (only people with a strong opinion answer.)"
independent variable (x-axis) includes at least one (discrete level) nominal value (car, man, white), the y- axis describes a second variable, a scale variable (counts or percentage)."
"Pareto Chart - CORRECT ANSWER=> A visual display of qualitative data. It is
a vertical bar graph in which the height of each bar represents frequency or relative frequency. The bars are positioned in order of decreasing height, with the tallest bar positioned at the left."
"Pictoral graphs - CORRECT ANSWER=> A visual depiction of data for an independent variable when
there are very few levels and a scale dependent variable. Each category uses a picture or symbol to represent its value on the scale dependent variable. *Its misleading when picturesare used in place of bars and the one picture appears so much larger."
"Pie chart - CORRECT ANSWER=> A visual display of qualitative data represented as percents of a
whole. It is a circle that is divided into sectors that represent categories. The area of each sector is proportional to the frequency of each category. A bar graph or table is easir to interpret. as a pie chart can be misleading.
- It should always add up to 100% find angles on pie chart by: relative frequency x 360= angles"
"Building a graph - CORRECT ANSWER=> Examine variables - independent (mostly x-axis) and
dependent (mostly y-axis) and type of variable - nominal, ordinal, or scale for each.
- One scale variable (frequencies) - histogram or frequency polygram.
- One scale independent variable and one scale dependent variable - scatterplot or line graph
- One nominal independent and one scale dependent - bar or Pareto graph
- Two or more nominal independent variables and one scale dependent - bar graph"
"Reading a bar graph - CORRECT ANSWER=> When a bar chart has two independent variables the first
score is what category are they in (men vs women), the second one woud be each categories level's score. It has two independent variables (nominal - either men or women, then men's two levels and womens two levels) and one scale dependent variable (score of each of the four independent variables.)"
"Guidelines for a Perfect Graph - CORRECT ANSWER=> 1. A clear, specific title
- Both axes labeled, left to right (even y-axis)
- Terms on the graph are the same as the text, no abbreviations.
- Units of measurements are included (time, distance, etc.)
- Axes start at 0 or have cut marks to indicate they do.
- If colors are used over gray scale they are clear.
- Chartjunk has been eliminated."
"Chartjunk - CORRECT ANSWER=> Any unnecessary information or feature in a graph that detracts
from a viewer's ability to understand the data.
- patterns on bars
- grid patterns behind bars
- shaddows on bars
- clipart
- eye straining colors"
"Statistic - CORRECT ANSWER=> A number based on a sample taken from a population; statistics are
usually symbolized by Latin letters
- statistic = sample M or X bar"
"Parameter - CORRECT ANSWER=> A number based on the whole population
"Measure of Central Tendency - CORRECT ANSWER=> is a value that represents a typical, or central,
entry of a data set. The three most commonly used measures of central tendency are: a. mean b. median c. mode"
"Mean, the arithmetic average - CORRECT ANSWER=> It is the sum of the data entries divided by the
number of entries. Typicall is the choice when selecting central tendency *When data is skewed to left, this will be the least central tendency as outliers lower the overall figures. *If it normally distrubuted it will be in the middle, along with the other two.
- If right skewed it will have highest score of the three central tendecies, because outliers with very high scores are added."
"Median - CORRECT ANSWER=> The value that lies in the middle of the data when the data set is
ordered. This measure is preferred when data is skewed. *First put data in order from lowest to highest. *Next, locate the center data point. If there is an odd number of entries, the median is the middle data entry. If the data set has an even number of entries, the median is the mean of the two middle data entries.
- Left skewed will make this central tendency be less than the mean
- Normal distribution will place this around the middle.
- Right skewed will give this a higher score than mean because mean is affected by the low numbers."
"Mode - CORRECT ANSWER=> It is the data entry that occurs with the greatest frequency, the highest
point on the graph. A data set can have one mode, more than one mode, or no mode. If no entry is repeated, the data set has no mode. Generally used:
- One score dominates a distribution.
"Sampling error - CORRECT ANSWER=> The difference between the results of a sample and those of a
population. appropriate sampling techniques must be used to ensure that inferences about the population are valid and these are not made.
- Sample size too small
- Sample is biased
- Samples were not independent"
"Sampling techniques - CORRECT ANSWER=> * Random
- Simple random sample
- Stratified sample
- Cluster sample
- Systematic sample
- Convenience sample"
"Random sample - CORRECT ANSWER=> Every member of the population has an equal chance of being
selected EX: using random digit dialing, researchers call 1400 ppl and ask what obstacles, such as childcare, keep them from exercising.
- One of two main types is social science research"
"Convenience sampling - CORRECT ANSWER=> Consists of only easily available members of the
population EX: questioning students as they leave a university library, a researcher asks 358 students about their drinking habits ___ sampling is used bc the students are chosen due to their convenience of location
- The other one of two types used in social science research"
"Generalizability - CORRECT ANSWER=> Refers to researchers' ability to apply findings from one sample
or in one context to other samples or contexts; also called external validity"
"Replication - CORRECT ANSWER=> Refers to the duplication of scientific results, ideally in a different
context or with a sample that has different characteristics"
"Volunteer sample/self selected sample - CORRECT ANSWER=> A special kind of convenience sample in
which participants actively choose to participate in a study"
"Simple random sample (SRS) - CORRECT ANSWER=> A sample in which every possible sample of the
same size has the same chance of being selected EX: each telephone number has an equal chance of being dialed, and all samples of 1400 have an equal chance of being selected"
"Personal probability - CORRECT ANSWER=> A person's own judgment about the likelihood that an
event will occur; also called subjective probability"
"Probability - CORRECT ANSWER=> Likelihood that a particular event will occur"
"Expected relative-frequency probability - CORRECT ANSWER=> The likelihood of an event occurring
based on the actual outcome of many, many trials"
"Trial - CORRECT ANSWER=> Each repetition or observation of an experiment"
"Outcome - CORRECT ANSWER=> A possible result of a probability experiment"
"Success - CORRECT ANSWER=> The outcome for which we're trying to determine the probability"
"Control group - CORRECT ANSWER=> In an experiment, the group that is not exposed to the
treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment."
"Experiment group - CORRECT ANSWER=> a level of the independent variabloe that receives the
treatment or intervention of interest in an experiment"
"Statistics - CORRECT ANSWER=> *The science of collecting, organizing, analyzing, and interpreting
data in order to make decisions *Derived from the Latin word "status" meaning state involves more of counting births & deaths *Divided into 2 fields (descriptive & inferential)"
